Low forced vital capacity is associated with poor prognosis in physiologically stable non-IPF interstitial lung disease

<title>Extract</title> Current guidelines define progressive pulmonary fibrosis (PPF) as the presence of at least two of the following three changes within 12 months—worsening symptoms, lung function decline, or new/extending radiographic abnormalities [1, 2]. However, limiting assessment to subsequent progression may miss high–risk patients: those presenting with severely impaired lung function may meet none of the criteria if later tests remain unchanged, delaying therapy initiation and close monitoring. Therefore, we examined whether baseline forced vital capacity (FVC) was associated with an increased risk of lung transplantation or death in non-idiopathic pulmonary fibrosis (non-IPF) interstitial lung disease (ILD) patients whose FVC declined by <5 percentage points predicted during the first year after diagnosis. We hypothesized that a reduced FVC measurement, even in the absence of further decline, signals advanced disease and portends poorer outcomes.